[{"id":169100,"pmid":28803780,"pmcid":null,"title":"Methylation of DNA Ligase 1 by G9a/GLP Recruits UHRF1 to Replicating DNA and Regulates DNA Methylation.","year":2017,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"DNA methylation is an essential epigenetic mark in mammals that has to be re-established after each round of DNA replication. The protein UHRF1 is essential for this process; it has been proposed that the protein targets newly replicated DNA by cooperatively binding hemi-methylated DNA and H3K9me2/3, but this model leaves a number of questions unanswered. Here, we present evidence for a direct recruitment of UHRF1 by the replication machinery via DNA ligase 1 (LIG1). A histone H3K9-like mimic within LIG1 is methylated by G9a and GLP and, compared with H3K9me2/3, more avidly binds UHRF1. Interaction with methylated LIG1 promotes the recruitment of UHRF1 to DNA replication sites and is required for DNA methylation maintenance. These results further elucidate the function of UHRF1, identify a non-histone target of G9a and GLP, and provide an example of a histone mimic that coordinates DNA replication and DNA methylation maintenance.","journal":null,"figures":[],"_authors":null},{"id":169099,"pmid":28394343,"pmcid":null,"title":"PIM1 induces cellular senescence through phosphorylation of UHRF1 at Ser311.","year":2017,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"PIM1 is a proto-oncogene, encoding a serine/threonine protein kinase that regulates cell proliferation, survival, differentiation and apoptosis. Previous reports suggest that overexpression of PIM1 can induce cellular senescence. However, the molecular mechanism underlying this process is not fully understood. Here we report that UHRF1 is a novel substrate of PIM1 kinase, which could be phosphorylated at Ser311 and therefore promoted to degradation. Our data demonstrates that PIM1 destabilizes UHRF1, leading to DNA hypomethylation, which consequently results in genomic instability, increased p16 expression and subsequent induction of cellular senescence. Taken together, our results suggest that down-regulation of UHRF1 is an important mechanism of PIM1-mediated cellular senescence.","journal":null,"figures":[],"_authors":null},{"id":121810,"pmid":28334952,"pmcid":null,"title":"DNMT1 mutations found in HSANIE patients affect interaction with UHRF1 and neuronal differentiation.","year":2017,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"DNMT1 is recruited to substrate sites by PCNA and UHRF1 to maintain DNA methylation after replication. The cell cycle dependent recruitment of DNMT1 is mediated by the PCNA-binding domain (PBD) and the targeting sequence (TS) within the N-terminal regulatory domain. The TS domain was found to be mutated in patients suffering from hereditary sensory and autonomic neuropathies with dementia and hearing loss (HSANIE) and autosomal dominant cerebellar ataxia deafness and narcolepsy (ADCA-DN) and is associated with global hypomethylation and site specific hypermethylation. With functional complementation assays in mouse embryonic stem cells, we showed that DNMT1 mutations P496Y and Y500C identified in HSANIE patients not only impair DNMT1 heterochromatin association, but also UHRF1 interaction resulting in hypomethylation. Similar DNA methylation defects were observed when DNMT1 interacting domains in UHRF1, the UBL and the SRA domain, were deleted. With cell-based assays, we could show that HSANIE associated mutations perturb DNMT1 heterochromatin association and catalytic complex formation at methylation sites and decrease protein stability in late S and G2 phase. To investigate the neuronal phenotype of HSANIE mutations, we performed DNMT1 rescue assays and could show that cells expressing mutated DNMT1 were prone to apoptosis and failed to differentiate into neuronal lineage. Our results provide insights into the molecular basis of DNMT1 dysfunction in HSANIE patients and emphasize the importance of the TS domain in the regulation of DNA methylation in pluripotent and differentiating cells.","journal":null,"figures":[],"_authors":null},{"id":109707,"pmid":28285359,"pmcid":null,"title":"Globular adiponectin inhibits leptin-stimulated esophageal adenocarcinoma cell proliferation via adiponectin receptor 2-mediated suppression of UHRF1.","year":2017,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"Esophageal adenocarcinoma (EAC) is one of the most common malignancies in the world which is associated the increased prevalence of obesity. In the context of obesity, leptin can directly contribute to progression of EAC. Adiponectin inhibits leptin-induced oncogenic signaling in EAC cells. However, the exact molecular mechanisms linking obesity, adipokines, and EAC remain far from completely understood. In the present study, we tested the role of ubiquitin-like with PHD and ring finger domains 1 (UHRF1) in adiponectin-induced protective effects against leptin-induced EAC cell proliferation. We found that globular adiponectin (gAD) significantly inhibited leptin-induced increase of cell proliferation and decrease of apoptosis in OE 19 cells. Moreover, leptin-induced increase of UHRF1 expression was suppressed by gAD. Compared with normal controls, UHRF1 expression was markedly increased in EAC tissues and cell lines. Silence of UHRF1 increased the expression of cleaved caspase 3 and 9 and Bax, reduced the expression of Bcl-2, promoted apoptosis, and inhibited cell proliferation in OE 19 cells. Overexpression of UHRF1 significantly blocked gAD-induced decrease of cell proliferation and increase of apoptosis in leptin-treated cells. Silence of adiponectin receptor 1/2 (AdipoR1/2) could inhibit gAD-induced decrease of cell proliferation and increase of apoptosis in leptin-treated cells. Silence of AdipoR2, but not AdipoR1, suppressed gAD-induced decrease of UHRF1 expression in leptin-treated cells. The results indicated that gAD inhibited the prooncogenic effects of leptin via AdipoR2-mediated suppression of UHRF1. Our study provides novel insights into the role of UHRF1 in the development of EAC and the mechanism of antitumor effect of gAD.","journal":null,"figures":[],"_authors":null},{"id":169098,"pmid":28128913,"pmcid":null,"title":"Overexpression of UHRF1 gene correlates with the major clinicopathological parameters in urinary bladder cancer.","year":null,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"Recently, expression of the UHRF1 gene was found to be up-regulated in numerous neoplasms, including the urinary bladder transitional cell carcinoma (TCC).","journal":null,"figures":[],"_authors":null},{"id":96,"pmid":28112733,"pmcid":null,"title":"Site-specific mapping of the human SUMO proteome reveals co-modification with phosphorylation.","year":2017,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"Small ubiquitin-like modifiers (SUMOs) are post-translational modifications (PTMs) that regulate nuclear cellular processes. Here we used an augmented K0-SUMO proteomics strategy to identify 40,765 SUMO acceptor sites and quantify their fractional contribution for 6,747 human proteins. Structural-predictive analyses revealed that lysines residing in disordered regions are preferentially targeted by SUMO, in notable contrast to other widespread lysine modifications. In our data set, we identified 807 SUMOylated peptides that were co-modified by phosphorylation, along with dozens of SUMOylated peptides that were co-modified by ubiquitylation, acetylation and methylation. Notably, 9% of the identified SUMOylome occurred proximal to phosphorylation, and numerous SUMOylation sites were found to be fully dependent on prior phosphorylation events. SUMO-proximal phosphorylation occurred primarily in a proline-directed manner, and inhibition of cyclin-dependent kinases dynamically affected co-modification. Collectively, we present a comprehensive analysis of the SUMOylated proteome, uncovering the structural preferences for SUMO and providing system-wide evidence for a remarkable degree of cross-talk between SUMOylation and other major PTMs.","journal":null,"figures":[],"_authors":null},{"id":83760,"pmid":28100769,"pmcid":null,"title":"The Ubiquitin-like with PHD and Ring Finger Domains 1 (UHRF1)/DNA Methyltransferase 1 (DNMT1) Axis Is a Primary Regulator of Cell Senescence.","year":2017,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"As senescence develops, cells sequentially acquire diverse senescent phenotypes along with simultaneous multistage gene reprogramming. It remains unclear what acts as the key regulator of the collective changes in gene expression at initiation of senescent reprogramming. Here we analyzed time series gene expression profiles obtained in two different senescence models in human diploid fibroblasts: replicative senescence and H2O2-induced senescence. Our results demonstrate that suppression of DNA methyltransferase 1 (DNMT1)-mediated DNA methylation activity was an initial event prior to the display of senescent phenotypes. We identified seven DNMT1-interacting proteins, ubiquitin-like with PHD and ring finger domains 1 (UHRF1), EZH2, CHEK1, SUV39H1, CBX5, PARP1, and HELLS (also known as LSH (lymphoid-specific helicase) 1), as being commonly down-regulated at the same time point as DNMT1 in both senescence models. Knockdown experiments revealed that, among the DNMT1-interacting proteins, only UHRF1 knockdown suppressed DNMT1 transcription. However, UHRF1 overexpression alone did not induce DNMT1 expression, indicating that UHRF1 was essential but not sufficient for DNMT1 transcription. Although UHRF1 knockdown effectively induced senescence, this was significantly attenuated by DNMT1 overexpression, clearly implicating the UHRF1/DNMT1 axis in senescence. Bioinformatics analysis further identified WNT5A as a downstream effector of UHRF1/DNMT1-mediated senescence. Senescence-associated hypomethylation was found at base pairs -1569 to -1363 from the transcription start site of the WNT5A gene in senescent human diploid fibroblasts. As expected, WNT5A overexpression induced senescent phenotypes. Overall, our results indicate that decreased UHRF1 expression is a key initial event in the suppression of DNMT1-mediated DNA methylation and in the consequent induction of senescence via increasing WNT5A expression.","journal":null,"figures":[],"_authors":null},{"id":169097,"pmid":27839516,"pmcid":null,"title":"Signalling pathways in UHRF1-dependent regulation of tumor suppressor genes in cancer.","year":2016,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"Epigenetic silencing of tumor suppressor genes (TSGs) through DNA methylation and histone changes is a main hallmark of cancer. Ubiquitin-like with PHD and RING Finger domains 1 (UHRF1) is a potent oncogene overexpressed in various solid and haematological tumors and its high expression levels are associated with decreased expression of several TSGs including p16 INK4A , BRCA1, PPARG and KiSS1. Using its several functional domains, UHRF1 creates a strong coordinated dialogue between DNA methylation and histone post-translation modification changes causing the epigenetic silencing of TSGs which allows cancer cells to escape apoptosis. To ensure the silencing of TSGs during cell division, UHRF1 recruits several enzymes including histone deacetylase 1 (HDAC1), DNA methyltransferase 1 (DNMT1) and histone lysine methyltransferases G9a and Suv39H1 to the right place at the right moment. Several in vitro and in vivo works have reported the direct implication of the epigenetic player UHRF1 in tumorigenesis through the repression of TSGs expression and suggested UHRF1 as a promising target for cancer treatment. This review describes the molecular mechanisms underlying UHRF1 regulation in cancer and discusses its importance as a therapeutic target to induce the reactivation of TSGs and subsequent apoptosis.","journal":null,"figures":[],"_authors":null},{"id":169096,"pmid":27595565,"pmcid":null,"title":"Hemi-methylated DNA regulates DNA methylation inheritance through allosteric activation of H3 ubiquitylation by UHRF1.","year":2016,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"The epigenetic inheritance of DNA methylation requires UHRF1, a histone- and DNA-binding RING E3 ubiquitin ligase that recruits DNMT1 to sites of newly replicated DNA through ubiquitylation of histone H3. UHRF1 binds DNA with selectivity towards hemi-methylated CpGs (HeDNA); however, the contribution of HeDNA sensing to UHRF1 function remains elusive. Here, we reveal that the interaction of UHRF1 with HeDNA is required for DNA methylation but is dispensable for chromatin interaction, which is governed by reciprocal positive cooperativity between the UHRF1 histone- and DNA-binding domains. HeDNA recognition activates UHRF1 ubiquitylation towards multiple lysines on the H3 tail adjacent to the UHRF1 histone-binding site. Collectively, our studies are the first demonstrations of a DNA-protein interaction and an epigenetic modification directly regulating E3 ubiquitin ligase activity. They also define an orchestrated epigenetic control mechanism involving modifications both to histones and DNA that facilitate UHRF1 chromatin targeting, H3 ubiquitylation, and DNA methylation inheritance.","journal":null,"figures":[],"_authors":null},{"id":169095,"pmid":27489107,"pmcid":null,"title":"Regulation of Ubiquitin-like with Plant Homeodomain and RING Finger Domain 1 (UHRF1) Protein Stability by Heat Shock Protein 90 Chaperone Machinery.","year":2016,"pages":null,"doi":null,"keywords":[],"mesh":[],"abstractText":"As a protein critical for DNA maintenance methylation and cell proliferation, UHRF1 is frequently highly expressed in various human cancers and is considered as a drug target for cancer therapy. In a high throughput screening for small molecules that induce UHRF1 protein degradation, we have identified the HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG). We present evidence that UHRF1 interacts with HSP90 chaperone complex and is a novel HSP90 client protein. Pharmacological inhibition of HSP90 with 17-AAG or 17-dimethylaminoethylamino-17-demethoxygeldanamycin results in UHRF1 ubiquitination and proteasome-dependent degradation. Interestingly, this HSP90 inhibitor-induced UHRF1 degradation is independent of CHIP and CUL5, two previously identified ubiquitin E3 ligases for HSP90 client proteins. In addition, this degradation is dependent neither on the intrinsic E3 ligase of UHRF1 nor on the E3 ligase SCF(?-TRCP) that has been implicated in regulation of UHRF1 stability. We also provide evidence that HSP90 inhibitors may suppress cancer cell proliferation in part through its induced UHRF1 degradation. Taken together, our results identify UHRF1 as a novel HSP90 client protein and shed light on the regulation of UHRF1 stability and function.","journal":null,"figures":[],"_authors":null}]